The objectives of each Vanguard Clinical Center is to cooperate with the Clinical Coordinating Center in developing, implementing and refining the overall program to ensure its feasibility and optimize it operationally before the additional Clinical Centers commence recruitment. The Vanguard Clinical Centers are to assist in the development, testing and implementation of the forms/questionnaires and procedures needed to recruit a group of postmenopausal U.S. women age 50-79, randomize them to a number of interventions, ensure adherence and adequate follow-up, and collect and transmit data and biological samples as needed for the ascertainment of the outcomes of the Clinical Trial and Observational Study. Major outcome will be coronary heart disease, breast neoplasms and osteoporosis.